Problems with 393 Motors

Recently my team got a load of new 393 motors.

I found that out of the box, all of the motors made clicking noises when rotated in a counter-clockwise direction, but when rotated in a clockwise direction, they were fine. I opened the motors to find there was very little lubricant inside, so I lubricated them. The problem continued.

I changed out the gears in the motors for other torque gears. The problem still continued.

Here’s the interesting part. I changed the gears out for speed gears (1.6:1) and suddenly, the motors were fine. No clicking.

So basically my question is, has anyone else encountered this issue with new 393 motors? If anyone else has, did you find any way to fix it? Considering that 4 of the motors that I have opened have ALL had this problem, I’m a little worried that it is a manufacturing fault, which would be a real pain, as some of these motors need to be used on torque mode.

I think we might have encounter something like this but im not sure if its exactly what your saying… And a question are there new 393 motors, because i think the spec increase since last year. I remember the high speed setting had 8.4 nm torque now it has 9.2? But as far as the issue, i believe the clicking noise could just mean nothing, because sometimes the motors make noises and they are fine, but im not sure. :confused:

I’ve seen many times across the forums that the motors have to be broken in. Try running them without a load for a few minutes nonstop and see if the problem persists.

Other than that, can’t say much more since we haven’t made our new order yet :confused:

We have had motors that have come straight from the packet that don’t spin at all, or only spin in one direction, we have also had motors that rattle. But I don’t think we have had clicking motors before.

Is this rotation being done by forcing the output shaft to turn by mechanically turning it or by electrically driving the motor?

It happened when turning the output shaft by hand. I’m going to try drive them electrically today under some load and see if the problem continues.

VEX recently updated the specs after they did more testing with the motors. Also, the motors are constantly being updated in small ways; there’s a number on each motor specifying the build.

As for the problem being discussed, we have experienced something similar many times with 2-Wire 269 Motors, but haven’t really had any issue at all with the 393 Motors (yet).


I don’t think the motors have changed, as far as I can tell, the wiki was updated to reflect the actual measured spec of the motor rather than the original design spec. New motors seem to have the same part numbers on internal components as old motors. I will do more tests when the school year starts and I can get hold of the motors we used last year.

The motors are very highly geared internally and it is a miraclel that you can manually turn them at all. We advise people to never manually turn them. I suspect that there is nothing wrong with your motors.